Mechanisms inducing compressive stress during electrodeposition of Ni

The evolution of stress during electrodeposition of Ni films on Au substrates has been investigated as a function of bath chemistry and deposition conditions to examine the microstructural origins of the compressive stress observed during deposition from an additive-free sulfamate bath. Three likely mechanisms for the generation of compressive stress in this system were investigated: interstitial hydrogen/impurity incorporation, capillarity stress, and a chemical-potential gradient driven atom incorporation model. Only the last model, the chemical-potential gradient model, could not be discounted as the active mechanism. However, further study is required to verify that this is the primary compressive stress generation mechanism.